You also need to factor in the decimation of Venues that put on Live Music.
20 years or so ago, there were far more venues operating than there are now, and a lot of them actively put on and promoted new & upcoming bands, playing original music.
It seems that fewer venues are willing to take the risk of putting on bands, and those that do, want bands that'll play known music (popular covers) in order to get the punters through the door.